Inorganic fertilizers such as ammonium phosphates, ammonium nitrates, potassium nitrates, potassium chlorides, potassium sulfates, and the like, all are well known. Methods of manufacturing these inorganic fertilizers, as well as methods of processing the fertilizers into particles via prill and granulation techniques, also are well known. The resulting particulate fertilizers, however, often exhibit an undesirable level of dust formation. The fertilizer granular particles easily break into smaller particles resulting in a substantial amount of dust being created when handled, transported, and when eventually applied to the soil. Also, the granular fertilizer particles often tend to cake when stored and transported in bulk such that substantial amounts of the initial free flowing particulate fertilizer agglomerates into solid, substantially integral masses.
Fertilizer dust emission is an increasingly serious problem creating a growing concern about atmospheric pollution and its possible ecological and toxicological effects. While it is preferable to produce non-dusty fertilizer particles, it often is necessary to resort to special antidust treatments due to the difficulty in manufacturing useable particulate fertilizer that do not emit dust.
The prior art has focused primarily on the treatment of particulate fertilizers with petroleum oils and waxes. However, there are disadvantages involved in using these treatment methods. Oils tend to volatilize and/or soak into the fertilizer with time and lose their effectiveness, while waxes are difficult to handle and often require special heated application equipment. Other proposed treatment methods involve application of an aqueous lignosulfonate solution, other liquid fertilizers, or water to the fertilizer particles. While liquid treatment compositions, such as these, may reduce the fertilizer dust levels, the liquid compositions coated on the fertilizer particles tend to promote caking of the granular fertilizer particles. Therefore, there still exists a need to provide a method of treating granular (particulate) fertilizer particles which not only reduces the amount of dust produced when the fertilizer particles are manufactured, handled, transported, and applied to the soil, but also lessens the fertilizer particles' tendency to cake during storage and bulk transport.